http://www.ideafordummies.com/install.html

R and r ovation preamp

not sure about your "jet" termonology

if it's an ovation  not an applause it has a lifetime warranty  BUT electronics are not included in that warranty.

If it's relatively recent the whole preamp pops out with a button allowing access to the battery ampng other things.

the Pickup  ...is a piezo transducer it is a thin strip  under the bridge saddle. its wire goes through the bridge under the saddle
if this is a round soundhole ovation.. you use a mirror and light inside the guitar body and work through the soundhole.

If it is one with the series of small holes...on the top lower bout there is a large circular plug that has to come out of the back of the body.

Best place for replacements is Stewart Macdonald.

They also have a mirror that folds,,,open it up when inside the body

Note that problems with these are USUALLY jack problems. The transducers usually don't go bad unless someone physically mauls them

Note there are 1/8 and 3/32 transducers.... They are NOT interchangeable.

The last tube sets I put in mine were chinese st shape "Chinese 6L6GC Small ST Shape"  from Danny's amp service in NJ  with his label

I THINK the ones antique radio supply (tubesandmore.com) are the same thing...39USD for the quad.

FWIW those sets were bought in 94  still working.

QuoteANYTIME powertubes a changed any GOOD technician the bias is adjusted

well it's not truly an normal cathode bias ...but the point was there is no way to "adjust"

Most cathode bias involve substituting different values of resistors... not "adjusting" a pot

Personally if it's "within limits" as such I never change resistors. If I have to suddenly throw in new tubes in a performance I prefer the resistors be the factory values. I've actually seldom had tubes go performing....transportation is usually the cause of unplanned tube changes for me.

As JM says this one is even different. There simply is no way to adjust it.

The symptoms described are somewhat common and usually caused by a shorted driver transistor q7 or q9 depending on which tube pair is acting up.



I've had to do this twice on one of my VTX once on the other.  that's around  5000 hours of use.

VTX is cathode bias  there is no adjustment to change.

If the tubes were red for more than a very brief period of time...particularly if they are recent manufacture tubes they ARE damaged, ( Current tubes have more metal impurities AND are not as deep a vacuum as old US and British made) how badly depends on whose tubes and how long the red.  Red plating causes metal impurities to build as gas in the tube. I would check the tubes before throwing them away but you would need a tube tester for that.

Use a matched pair or better a quad for best results.

This amp has very little tone difference with different ones Ruby Tube set from musicians friend is proabably the cheapest that's not junk.


BTW while you are doing all this ...testing....make sure you have the power on LOW setting it reduces the voltage to the tubes.

Amp usually sounds better there anyway ....I've only used that amp on High in auditoriums.

https://docs.google.com/fileview?id=0B5Lr8KpxtYCuYWQwZDY5M2YtOThjYy00NzE2LWEyMzYtYWI2ZTdkMDAyZDc1&hl=en&authkey=CN3fuK0M

heritage vtx schematics   

yes if the resistors check the same (good) one of those transistors q7 q9  I always change q6 and q8 along with them...

You'll need the cross reference I uploaded...you'll never find the original peavey #s.

You will need to remove the transistors from the circuit to test them properly.

Make sure you drain the caps before sticking your hands in there.

I've had this happen when a driver transistor goes Thats the large transistor on the heat sink. It's happened about every seven years actually.

If the resistors check out...look at the transistors.  I've always changed the pair and the transistor just before it in the schematic.
Careful of the latter Subs with the same pin out are rare.

(q6 q7 q8 q9)

just a thought here...you probably created a secondary problem with the "expensive silver compound"

take a look at the spec sheets.... those silver compunds are advertised as "highly conductive thermally and electrically" (BTW mouser sells it in bulk...not as expensive those little tubes are aimed at computer fanboys)

This WOULD work for To3 cases though... or circuits where to TO 220 case is grounded ...ususually single sided supply...

did you clean it off everything meticulously with solvent?

I would appreciate a little help as I'm stumped
One channel output power amp was burnt/toasted.  Don't know why. I picked this up for my son on ebay. Basket case

Cheap

Q11, Q10, Q5, Q9 were toasted as were r17 r25 r21
R26 was open cracked

Q6 was missing !?

D4 was shorted

R26 was open


I also changed Q8 although it tested good.

Fixed two traces where the cooked parts damaged the board.

I replaced r26 and 27
Now that channel works!

All I get on the right channel is noise and loud buzz.

I had bought extra output parts so q101 thru q111 were changed...still bad.
R 126 127 were changed too
Voltages are ok at TP4  not at tp5 didn't write it down but was really low.


Have multimeters but no scope signal generator etc.

All the jacks seem to be working properly


schematics are here:



https://docs.google.com/fileview?id=0B_cPagiySScIMTc0YzQ2ZDktZjNlZS00ZmIyLTkwZDEtNDM1ZmNhZGU4MDIy&hl=en

Preamp works  going into another amp through the mixed jack.



Solved:  Careful of this schematic....parts< than 100 are LEFT channel >100 right


...schematic says..."left channel same as right  add 100 to parts....

http://www.amazon.com/Electric-Guitar-Amplifier-Handbook-Jack/dp/1882580486/ref=sr_1_1?ie=UTF8&s=books&qid=1277580289&sr=8-1

The book is available from Amazon


FWIW they also sell this  http://www.amazon.com/Bry-Melvin/e/B0033QZU12/ref=sr_tc_2_0?qid=1277580409&sr=1-2-ent

shameless plug 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320545833659&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320447070251&ssPageName=STRK:MEWAX:IT

couple of links for boards  cheap

I've only used these with TDA2050 though... and I haven't had time to finish the project  (studio reference powered speakers) so I can't guarantee their quality

QuoteNo other passive tone circuit I know of can pull the mid notch like HiWatt.

Curious  if that included the on guitar circuit board and tbx  (Eric Clapton signature strat)

I build (or have built) all of my strat type guitars with that circuit

I've never used a HiWatt.

Yes I know that's an "active" guitar setup...just curious of the comparison if someone has tried.

OK ....managed to find someone at SLM that knew what I was talking about....they say that and a large number of crate amps used the same one:

190 ohm input 2575 output. 8bb2c1b

The tank is not available anywhere I find

Tubes and more (antique radio supply in TEMPE AZ) carries an 8bb2a1b  which will work...however  may have to alter the grounding.

I know I answered my own question...just wanted to get it in the archives for the next person running a search.